David Letterman wasn’t the slightest bit intimidated by Robin Williams the first time he met the comedian 38 years ago at The Comedy Store in Los Angeles. That is, until Williams got on stage. “It’s like nothing we had ever seen before,” Letterman remembered. “We’re like morning dew. He comes in like a hurricane.”

Letterman’s show was taking a break last week so he wasn’t able to publicly remember Williams, who died August 11 at age 63, until Monday evening. The late night host took 10 minutes to tell stories about Williams, including one about the time Williams landed Letterman a guest spot on popular ’70s sitcom Mork and Mindy.

“This is a double-edged sword, because he did it only because he was trying to help other fledgling, starting-out comics,” Letterman said. “The other side of the sword is I had no business being on that show. I have no business being on this show.”

Once Letterman got his own show, Williams was a frequent guest who made the host’s job easy. “All I had to do is sit here and watch the machine,” Letterman said. “People were drawn to him because of this electricity, this whatever it was that he radiated, that propelled him and powered him.”

Letterman gave us a glimpse of just how electric Williams’ late night appearances were with a compilation video of his times on the show. The video features some of Williams’ trademark physical, over-the-top comedy, but it also focuses on Williams’ laughter, how he threw his head back and guffawed.

“It will make you laugh,” Letterman said before playing the video. “And really, that’s what we should take from this, is he could make you laugh under any circumstances.”